COMPUTER NETWORKS

PRACTICAL FILE

GURU NANAK INSTITUTE OF MANAGEMENT

Affiliated to GGSIPU
(Guru Gobind Singh Indraprastha University)

Submitted to: Submitted by:

Mr. Nilesh Dokania Aman Suneja
(Asst. Professor) 3713004422
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INDEX
Course Code: MCA-161

Course Name: Computer Networks Lab

S. No. Detailed Statement of the Lab Exercise Page No.

1. Overview of CISCO PACKET TRACER 3-5

2. Overview of IP Address 6-7

3. Design Ethernet Cables: Crossover Cable, Straight through Cable, Rollover 8-9
Cable
4. Demonstrate to connect two computers without connecting devices 10-12

5. Demonstrate to connect two computers with connecting devices 13-16

6. Demonstrate the use of Hub to make a connection 17-20

7. Demonstrate the use of Switch to make a connection 21-23

8. Overview of Router & Wireless Router 24-30

9. Demonstrate the use of router to make a connection 31-34

10. Demonstrate the use of Wireless router to make a connection 35-39

11. Introduction to Network Address Translation 40-41

12. Overview of different interfaces in router 42-43

13 Implement IP Subnetting in IPV4 44-45

14 Implement IP routing using RIP 46-48

15 Implement IP routing using IGRP 49-52

16 Managing traffic with Standard IP & Extended IP Access List 53-57

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Ques 1
Overview of CISCO Packet Tracer

Ans.
Cisco Packet Tracer is a comprehensive, networking technology teaching and learning
program that offers a unique combination of realistic simulation and visualization
experiences, assessment and activity authoring capabilities, and opportunities for multiuser
collaboration and competition.
When we open CISCO Packet Tracer, by default we are presented with the following interface.

The initial interface is divided into 10 components:

1. Menu Bar:

This is a common menu found in all software applications; it is used to open, save,
print, change preferences, and so on.

2. Main Tool Bar:

This bar provides shortcut icons to menu options that are commonly accessed, such
as open, save, zoom, undo, and redo, and on the right-hand side is an icon for entering
network information for the current network.
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3. Common Tool Bar:

This toolbar provides controls for manipulating topologies, such as select, move
layout, place note, delete, inspect, resize shape, and add simple/complex PDU.

4. Logical/Physical Workspace Tabs:

These tabs allow you to toggle between the Logical and Physical work areas.

5. Workspace:

This is the area where topologies are created and simulations are displayed.

6. Realtime/Simulation Bar:

These tabs are used to toggle between the real-time and simulation modes. Buttons
are also provided to control the time, and to capture the packets.

7. Network Component Box:

This component contains all of the network and end devices available with Packet
Tracer, and is further divided into two areas:
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a. Device-Type Selection Box:

This area contains device categories.

b. Device-Specific Selection Box:

When a device category is selected, this selection box displays the different
device models within that category.

8. User-created packet box:

We can create highly-customized packets to test their topology from this area, and
the results are displayed as a list.
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Ques 2
Overview of IP Address.

Ans.
All the computers of the world on the Internet network communicate with each other with
underground or underwater cables or wirelessly. If I want to download a file from the
internet or load a web page or literally do anything related to the internet, my computer
must have an address so that other computers can find and locate mine in order to deliver
that particular file or webpage that I am requesting. In technical terms, that address is
called IP Address or Internet Protocol Address.
Or in other words, an IP address is a unique address that is used to identify computers or
nodes on the internet. This address is just a string of numbers written in a certain format. It
is generally expressed in a set of numbers for example 192.155.12.1. Here each number in
the set is from 0 to 255 range. Or we can say that a full IP address range from 0.0.0.0 to
255.255.255.255. And these IP addresses are assigned by IANA (known as Internet
Corporation for Internet Assigned Numbers Authority).
IP or Internet Protocol is just a set of rules that makes the internet work.
An Internet Service Provider (ISP) will generally assign either a static IP address (always the
same) or a dynamic address (changes every time one logs on). ISPs and organizations usually
apply to the InterNIC for a range of IP addresses so that all clients have similar addresses.
Versions of IP Address:
IP Address is of two types:
IPv4: Internet Protocol version 4. It consists of 4 numbers separated by the dots. Each
number can be from 0-255 in decimal numbers. But computers do not understand decimal
numbers, they instead change them to binary numbers which are only 0 and 1. Therefore,
in binary, this (0-255) range can be written as (00000000 – 11111111). Since each number
N can be represented by a group of 8-digit binary digits. So, a whole IPv4 binary address can
be represented by 32-bits of binary digits. In IPv4, a unique sequence of bits is assigned to
a computer, so a total of (2^32) devices approximately = 4,294,967,296 can be assigned
with IPv4. IPv4 can be written as:
189.123.123.90
Classes of IPv4:
IP Class Address Range Maximum Number of Range
Networks
Class A 0-127 127(27-1) 0.0.0.0 to 127.255.255.255
Class B 128-191 16384 128.0.0.0 to 191.255.255.255
Class C 192-223 2097152 192.0.0.0 to 223.255.255.255
Class D 224-239 Reserve for Multitasking 224.0.0.0 to 239.255.255.255
Class E 240-254 Reserve for R&D 240.0.0.0 to 255.255.255.255

In dotted-decimal representation, an IP address is divided into four

octets, and based on which class the IP address belongs to its octets are
further divided into network ID and HOST ID. For Class A first octet
represents network ID as the prefix of the first octet is 0, it uses the
remaining 7 bits for network ID, for Class B first and second octets
represent network ID the prefix for class B is 10 so it uses the remaining
14 bits for network ID, for Class C first, second and third octet represents
network ID the prefix of class C is 110 so it uses the remaining 21 bits for
network ID, Class D, and Class E are reserved.
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IPv6: But, there is a problem with the IPv4 address. With IPv4, we can connect only the
above number of 4 billion devices uniquely, and apparently, there are much more devices
in the world to be connected to the internet. So, gradually we are making our way to IPv6
Address which is a 128-bit IP address. In human-friendly form, IPv6 is written as a group of
8 hexadecimal numbers separated with colons(:). But in the computer-friendly form, it can
be written as 128 bits of 0s and 1s. Since, a unique sequence of binary digits is given to
computers, smartphones, and other devices to be connected to the internet. So, via IPv6 a
total of (2^128) devices can be assigned with unique addresses which are actually more
than enough for upcoming future generations. IPv6 can be written as:
2011:0bd9:75c5:0000:0000:6b3e:0170:8394
IP Address can be classified into following types:
Public IP Address: This address is available publicly and it is assigned by your network
provider to your router, which further divides it to your devices. Public IP Addresses are of
two types,
• Dynamic IP Address
• Static IP Address
Private IP Address: This is an internal address of your device which are not routed to the
internet and no exchange of data can take place between a private address and the internet.
Shared IP addresses: Many websites use shared IP addresses where the traffic is not huge
and very much controllable, they decide to rent it to other similar websites so to make it
cost-friendly. Several companies and email sending servers use the same IP address (within
a single mail server) to cut down the cost so that they could save for the time the server is
idle.
Dedicated IP addresses: A dedicated IP Address is an address used by a single company or
an individual which gives them certain benefits using a private Secure Sockets Layer (SSL)
certificate which is not in the case of a shared IP address. It allows to access the website or
log in via File Transfer Protocol (FTP) by IP address instead of its domain name. It increases
the performance of the website when the traffic is high. It also protects from a shared IP
address that is black-listed due to spam.

A subnet mask is like an IP address, but for only internal usage within a network. Routers use
subnet masks to route data packets to the right place. Subnet masks are not indicated within
data packets traversing the Internet — those packets only indicate the destination IP address,
which a router will match with a subnet.
Suppose an IP packet is addressed to the IP address 192.0.2.15. This IP address is a Class C
network, so the network is identified by "192.0.2" (or to be technically precise, 192.0.2.0/24).
Network routers forward the packet to a host on the network indicated by "192.0.2."
Once the packet arrives at that network, a router within the network consults its routing table.
It does some binary mathematics using its subnet mask of 255.255.255.0, sees the device
address "15" (the rest of the IP address indicates the network), and calculates which subnet
the packet should go to. It forwards the packet to the router or switch responsible for
delivering packets within that subnet, and the packet arrives at IP address 192.0.2.15
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Ques 3
Design Ethernet Cables: Crossover Cable, Straight through Cable, Rollover Cable

Ans.
• Crossover Wired Cables:
Crossover wired cables (commonly called crossover cables) are very much like
Straight-Through cables with the exception that TX and RX lines are crossed (they are
at opposite positions on either end of the cable. Using the 568-B standard as an
example below, you will see that Pin 1 on connector A goes to Pin 3 on connector B.
Pin 2 on connector A goes to Pin 6 on connector B, etc. Crossover cables are most
commonly used to connect two hosts directly. Examples would be connecting a
computer directly to another computer, connecting a switch directly to another
switch, or connecting a router to a router. Note: While in the past, when connecting
two host devices directly, a crossover cable was required. Nowadays, most devices
have auto-sensing technology that detects the cable and device and crosses pairs when
needed.

• Straight-Through Wired Cable:

Straight-Through refers to cables that have the pin assignments on each end of the
cable. In other words, Pin 1 connector A goes to Pin 1 on connector B, Pin 2 to Pin 2,
etc. Straight-Through wired cables are most commonly used to connect a host to a
client. When we talk about cat5e patch cables, the Straight-Through wired cat5e patch
cable is used to connect computers, printers, and other network client devices to the
router switch or hub (the host device in this instance).
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• Rollover Wired Cables:

Rollover wired cables, most commonly called rollover cables, have opposite Pin
assignments on each end of the cable or, in other words, it is "rolled over." Pin 1 of
connector A would be connected to Pin 8 of connector B. Pin 2 of connector A would
be connected to Pin 7 of connector B and so on. Rollover cables, sometimes referred
to as Yost cables are most commonly used to connect to a device's console port to
make programming changes to the device. Unlike crossover and straight-wired cables,
rollover cables are not intended to carry data but instead create an interface with the
device.
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Ques 4
Demonstrate to connect two computers without connecting devices

Ans.
Steps:
1. Select two end devices, PC1 and PC2.

2. Connect both the devices using a copper cross-over cable.

3. Configure IP Addresses and Subnet Masks of both the devices. Make sure that both IP
Addresses belong to the same network.
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4. Right click on the device then click on Desktop → Command Prompt.

5. Use ipconfig to see the IP Address of the end device.

6. Use ping 192.168.2.3 (IP Address of the other PC on network) to see if there is
connection or not. It tries to send packet to another system and tell if connection is
established between them or not.
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Ques 5
Demonstrate to connect two computers with connecting devices

Ans.
Connecting 2 devices using a HUB.
Steps:
1. Select 2 devices and a HUB.

2. Connect every device with HUB using copper straight cable.

3. Configure IP Addresses of all devices and make sure all of them belong to same
network, also set their respective subnet masks.
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PC1 and PC2:

System Name IP Address Subnet Mask
PC1 192.168.0.1 255.255.255.0
PC2 192.168.0.2 255.255.255.0

4. Right click on the device then click on Desktop → Command Prompt.

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5. Use ipconfig to see the IP Address of the PC.

6. Use ping 192.168.0.2 (IP Address of any other system in network) to see if connection
is established or not, it will be checked by sending packets.
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Ques 6
Demonstrate the use of Hub to make a connection

Ans.
Connecting 5 devices using a HUB.
Steps:
1. Select 5 devices and a HUB.

2. Connect every device with HUB using copper straight cable.

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3. Configure IP Addresses of all devices and make sure all of them belong to same
network, also set their respective subnet masks.

PC1 to PC5:
System Name IP Address Subnet Mask
PC1 192.168.0.1 255.255.255.0
PC2 192.168.0.2 255.255.255.0
PC3 192.168.0.3 255.255.255.0
PC4 192.168.0.4 255.255.255.0
PC5 192.168.0.5 255.255.255.0

4. Right click on the device then click on Desktop → Command Prompt.

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5. Use ipconfig to see the IP Address of the PC.

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6. Use ping 192.168.0.5 (IP Address of any other system in network) to see if connection
is established or not, it will be checked by sending packets.
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Ques 7
Demonstrate the use of Switch to make a connection

Ans.
Connecting 2 devices using a SWITCH.
Steps:
1. Select 2 devices and a SWITCH.

2. Connect every device with SWITCH using copper straight cable.

3. Configure IP Addresses of all devices and make sure all of them belong to same
network, also set their respective subnet masks.

PC1 and PC2:

System Name IP Address Subnet Mask
PC1 192.168.0.1 255.255.255.0
PC2 192.168.0.2 255.255.255.0
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4. Right click on the device then click on Desktop → Command Prompt.

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5. Use ipconfig to see the IP Address of the PC.

6. Use ping 192.168.0.2 (IP Address of any other system in network) to see if connection
is established or not, it will be checked by sending packets.
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Ques 8
Overview of Router & Wireless Router

Ans.
Network routing is the process of selecting a path across one or more networks. The
principles of routing can apply to any type of network, from telephone networks to public
transportation. In packet-switching networks, such as the Internet, routing selects the paths
for Internet Protocol (IP) packets to travel from their origin to their destination. These
Internet routing decisions are made by specialized pieces of network hardware called routers.
In the diagram below, for a data packet to get from Computer A to Computer B, should it pass
through networks 1, 3, and 5 or networks 2 and 4? The packet will take a shorter path through
networks 2 and 4, but networks 1, 3, and 5 might be faster at forwarding packets than 2 and
4. These are the kinds of choices network routers constantly make.

Routers refer to internal routing tables to make decisions about how to route packets along
network paths. A routing table records the paths that packets should take to reach every
destination that the router is responsible for. Think of train timetables, which train
passengers consult to decide which train to catch. Routing tables are like that, but for network
paths rather than trains.
Routers work in the following way: when a router receives a packet, it reads the headers* of
the packet to see its intended destination, like the way a train conductor may check a
passenger's tickets to determine which train they should go on. It then determines where to
route the packet based on information in its routing tables.
Routers do this millions of times a second with millions of packets. As a packet travels to its
destination, it may be routed several times by different routers.
Routing tables can either be static or dynamic. Static routing tables do not change. A network
administrator manually sets up static routing tables. This essentially sets in stone the routes
data packets take across the network, unless the administrator manually updates the tables.
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Dynamic routing tables update automatically. Dynamic routers use various routing protocols
(IP, BGP, OSPF, RIP) to determine the shortest and fastest paths. They also make this
determination based on how long it takes packets to reach their destination — similar to the
way Google Maps, Waze, and other GPS services determine the best driving routes based on
past driving performance and current driving conditions.
Dynamic routing requires more computing power, which is why smaller networks may rely on
static routing. But for medium-sized and large networks, dynamic routing is much more
efficient.
The common metric values used for routing are:
Hop count: Hop count is defined as a metric that specifies the number of passes through
internetworking devices such as a router, a packet must travel in a route to move from source
to the destination.
Delay: It is a time taken by the router to process, queue and transmit a datagram to an
interface.
Bandwidth: The capacity of the link is known as a bandwidth of the link.
Load: Load refers to the degree to which the network resource such as a router or network
link is busy.
Reliability: Reliability is a metric factor may be composed of a fixed value. It depends on the
network links, and its value is measured dynamically.
*Packet headers are small bundles of data attached to packets that provide useful
information, including where the packet is coming from and where it is headed, like the
packing slip stamped on the outside of a mail parcel.
A router is a device that connects two or more packet-switched networks or subnetworks. It
works at Network Layer. It serves two primary functions: managing traffic between these
networks by forwarding data packets to their intended IP addresses, and allowing multiple
devices to use the same Internet connection.
There are several types of routers, but most routers pass data between LANs (local area
networks) and WANs (wide area networks). A LAN is a group of connected devices restricted
to a specific geographic area. A LAN usually requires a single router.
A WAN, by contrast, is a large network spread out over a vast geographic area. Large
organizations and companies that operate in multiple locations across the country, for
instance, will need separate LANs for each location, which then connect to the other LANs to
form a WAN. Because a WAN is distributed over a large area, it often necessitates multiple
routers and switches*.
*A network switch forwards data packets between groups of devices in the same network,
whereas a router forwards data between different networks.
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WIRED
Routers emulated in CISCO Packet Tracer:
CISCO 1841 ISR Router

The Cisco 1841 Integrated Services Router provides two fixed 10/100 (100BASE-TX) Ethernet
ports, two integrated High-Speed WAN Interface Card (HWIC) slots that are compatible with
WAN Interface Card (WICs) and Voice/WAN Interface Cards (VWICs), and one internal
Advanced Integration Module (AIM) slot.

CISCO 2620XM ISR Router

The Cisco 2620XM Multiservice Router provides a one-network module slot platform with
one fixed 10/100 (100BASE-TX) Ethernet port, two integrated WAN Interface Card (WIC) slots,
and one Advanced Integration Module (AIM) slot.

CISCO 2621XM ISR Router

The Cisco 2621XM Multiservice Router provides a one-network module slot platform with
two fixed 10/100 (100BASE-TX) Ethernet ports, two integrated WAN Interface Card (WIC)
slots, and one Advanced Integration Module (AIM) slot.
The 2621XM supports the same modules that the 2620XM supports.

And many other Routers.

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Modules provided for Routers

WIC Modules

Module Description
The WIC-1AM provides one internal V.90 analog modems. This WIC can be used for basic
telephone service connections. The WIC-1AM uses one port for connection to a standard
WIC-1AM telephone line, and the other port can be connected to a basic analog telephone for use
when the modem is idle.

The WIC-1ENET is a single-port 10 Mbps Ethernet interface card, for use with 10BASE-T
WIC-1ENET
Ethernet LANs.
The WIC-1T provides a single port serial connection to remote sites or legacy serial
network devices such as alarm systems, Synchronous Data Link Control (SDLC)
concentrators, and packet over SONET devices.
WIC-1T
Sync Max Speed : 2048 Mbit/s
Async Max Speed : 115.2 Kbit/s

The WIC-2AM card features dual RJ-11 connectors, which are used for basic telephone
service connections. The WIC-2AM has two internal V.90 analog modems to allow
WIC-2AM
multiple data communication connections. These WICs can be used for incoming or
outgoing analog modem calls.
The 2-port asynchronous/synchronous serial network module provides flexible multi-
protocol support, with each port individually configurable in synchronous or
asynchronous mode, offering mixed media dial support in a single chassis. Applications
for asynchronous/synchronous support include:
WIC-2T
- Low speed WAN aggregation (up to 128 Kbps),
- Dial-up modem support,
- Async or Sync connections to management ports of other equipment,
- Transport of legacy protocols such as Bi-sync and SDLC.

HWIC-4ESW The HWIC-4ESW provides four switching ports.

New module included in CiscoPacket Tracer 6.0.1Cisco ISR routers. This serial modules
allows out of band management of Cisco networking devices through their console port.
HWIC-8A
The HWIC-8A module allows the connection of 8 console cables using the octal cable,
each serial connection being mapped to a TCP port for telnet access.
The WIC cover plate provides protection for the internal electronic components. It also
WIC-Cover
helps maintain adequate cooling by normalizing airflow.

NETWORK Modules

Module Description
The NM-1E features a single Ethernet port that can connect a LAN backbone which can
NM-1E also support either six PRI connections to aggregate ISDN lines, or 24
synchronous/asynchronous ports.
The NM-1E2W provides a single Ethernet port with two WIC slots that can support a
NM-1E2W single Ethernet LAN, together with two serial/ISDN backhaul lines, and still allow multiple
serial or ISDN in the same chassis.
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The NM-1FE-FX Module provides one Fast-Ethernet interface for use with fiber media.
Ideal for a wide range of LAN applications, the Fast Ethernet network modules support
NM-1FE-FX
many internetworking features and standards. Single port network modules offer
autosensing 10/100BaseTX or 100BaseFX Ethernet.
The NM-1FE-TX Module provides one Fast-Ethernet interface for use with copper media.
Ideal for a wide range of LAN applications, the Fast Ethernet network modules support
NM-1FE-TX many internetworking features and standards. Single port network modules offer
autosensing 10/100BaseTX or 100BaseFX Ethernet. The TX (copper) version supports
virtual LAN (VLAN) deployment.
The NM-1FE2W Module provides one Fast-Ethernet interface for use with copper media,
in addition to two Wan Interface Card expansion slots. Ideal for a wide range of LAN
NM-1FE2W applications, the Fast Ethernet network modules support many internetworking features
and standards. Single port network modules offer autosensing 10/100BaseTX or
100BaseFX Ethernet. The TX (copper) version supports virtual LAN (VLAN) deployment.
The NM-2E2W provides two Ethernet ports with two WIC slots that can support two
NM-2E2W Ethernet LANs, together with two serial/ISDN backhaul lines, and still allow multiple serial
or ISDN in the same chassis.
The NM-2FE2W Module provides two Fast-Ethernet interfaces for use with copper media,
in addition to two Wan Interface Card expansion slots. Ideal for a wide range of LAN
NM-2FE2W
applications, the Fast Ethernet network modules support many internetworking features
and standards.
The NM-2W Module provides two WAN Interface Card expansion slots. It can be used
NM-2W with a broad range of interface cards, supporting a diverse array of physical media and
network protocols.
The 4-port asynchronous/synchronous serial network module provides flexible multi-
protocol support, with each port individually configurable in synchronous or
asynchronous mode, offering mixed-media dial support in a single chassis. Applications
NM-4A/S
for Asynchronous/Synchronous support include: Low speed WAN aggregation (up to 128
Kbps), dial-up modem support, Async or Sync connections to management ports of other
equipment, and transport of legacy protocols such as Bi-sync and SDLC.
The NM-4E features four Ethernet ports for multifunction solutions that require higher-
NM-4E
density Ethernet than the mixed-media network modules.
The 8-port asynchronous/synchronous serial network module provides flexible multi-
protocol support, with each port individually configurable in synchronous or
asynchronous mode, offering mixed-media dial support in a single chassis. Applications
NM-8A/S
for Asynchronous/Synchronous support include: Low speed WAN aggregation (up to 128
Kbps), dial-up modem support, Async or Sync connections to management ports of other
equipment, and transport of legacy protocols such as Bi-sync and SDLC.
The NM-8AM Integrated V.92 analog modem network module provides cost-effective
analog telephone service connectivity for lower-density remote-access service (RAS),
dial-out and fax-out modem access, asynchronous dial-on-demand routing (DDR) plus
NM-8AM
dial backup, and remote router management. Both the 8-port and 16-port versions use
RJ-11 jacks to connect the integrated modems to basic analog telephone lines on the
public switched telephone network (PSTN) or private telephony systems.
The NM cover plate provides protection for the internal electronic components. It also
NM-Cover
helps maintain adequate cooling by normalizing airflow.
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TRANSCEIVERS

Module Description
GLC-GE- The 100BASE-FX SFP module for Gigabit Ethernet ports, 1310 nm wavelength, 2 km over
100FX MMF.
Cisco GLC-LH-SMD 1000BASE-LX/LH SFP is made for Both Multimode and Single-Mode
Fibers. The 1000BASE-LX/LH SFP, compatible with the IEEE 802.3z 1000BASE-LX standard,
GLC-LH-
operates on standard single-mode fiber-optic link spans of up to 10 km and up to 550 m
SMD
on any multimode fibers. When used over legacy multimode fiber type, the transmitter
should be coupled through a mode conditioning patch cable.

Router’s Back Panel

The router’s ports where the cables are connected, a power button and a reset button are
provided.

Internet The internet port is where our broadband modem is connected.

Ethernet 1 to 4 These ports connect the router to the wired PCs and other Ethernet devices.
Reset Button There are 2 ways to reset the router’s factory defaults. Either press this reset
button, for about 5 seconds, or restore the defaults from the Administration-
Factory defaults tab of the router’s web-based utility.
Power port The Power port is where adapter is connected.

Router’s Front Panel

The router’s LEDs are located on the front panel.

Power Green. The POWER LED lights up and will stay on while the router is powered
on.
Ethernet 1 to 4 Green. These numbered LEDs, corresponding with the numbered ports on
the Router’s back panel, serve two purposes. The LED lights up when the
router is connected to a device through the corresponding port. If the LED is
flashing, the router is sending or receiving data over that port.
Internet Green. The INTERNET LED lights up when there is a connection through the
Internet.
Wireless Green. The WIRELESS LED lights up when there is a wireless connection. If the
LED is flashing, the router is sending or receiving data over the wireless
network.
Security Green. The SECURITY LED indicates when wireless security is enabled.
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WIRELESS

Wireless routers are commonly found in homes -- they're the hardware devices that Internet
service providers use to connect you to their cable or xDSL Internet network. A wireless
router, also called a Wi-Fi router, combines the networking functions of a wireless access
point and a router.
A router connects local networks to other local networks or to the Internet. A wireless access
point connects devices to the network wirelessly, using radio frequencies in the 900 MHz and
2.4, 3.6, 5, and 60 GHz frequency bands. The latest wireless routers are based on the IEEE
802.11ac Wave 2 standard, often shortened to Wave 2.
A wireless router is sometimes referred to as a WLAN (wireless local area network) device. A
wireless network is also called a Wi-Fi network.

Types of Wireless Router

• Desktop Wi-Fi Router
• Mobile Hotspot
• Portable Wi-Fi

Working of Wireless Router

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Ques 9
Demonstrate the use of router to make a connection

Ans.
Steps:
1. Select two end devices and two routers. (Here we have used Router-PTs because it
contains serial ports already.)

2. Connect the end devices to respected routers with Copper cross-over cables and
router to router with Serial DTE.

3. Configure the IP Address of the Systems (end-devices), they should belong to different
networks (Say PC1: 192.168.1.1 and PC2:192.168.2.1) also set their respective subnet
masks.

4. Configure the routers by following steps:

a. Switch on port status of Fast Ethernet 0/0.
b. Configure the IP Addresses for both routers as, if Router1 and PC1 are
connected then their fast ethernets must belong to same network. Similarly,
for Router 2 and PC2.
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c. Configure the Serial 2/0 for Router1 and Router2 by assigning the IP Address
of the same network to them. (Say 192.168.3.1 and 192.168.3.2).
d. Set port status of serial 2/0 to on and set the clock rate to 148000. (Same for
both routers)
e. Add the Ethernet 0/0 and Serial 2/0 IP Addresses to the RIP routing tables of
respective Routers.
RIP: Routing Information Protocol is a distance vector routing protocol, which
employs the hop count as a routing metric.

5. Now set the default gateways of the end devices (PC1 and PC2), which is the IP Address
of the fast Ethernet 0/0 of the respective routers.
Default Gateway: Node on a TCP/IP network that serves as an access point to another
network.

6. Right click on the device then click on Desktop → Command Prompt.

 33

7. Use ipconfig to see the IP Address of the PC.

 34

8. Ping the system PC2 from PC1.

Green triangles specify that the systems are connected and completely functioning.
 35

Ques 10
Demonstrate the use of Wireless router to make a connection

Ans.
Steps:
1. Take 2 devices, a PC (PC1) and a Laptop (Laptop1), and a wireless router (Linksys
WRT300N: Router1).

2. Go to the router settings → Go to Wireless → Enable the key and select WEP in
authentication. Enter the key.
 36

3. Now add module (Linksys-WMP300N) to the PC and Laptop.

4. Go to Desktop → PC Wireless. Do the following steps for both PC and Laptop.
 37

5. Go to Connect, there will be wireless router name, ch and signal.

6. Click on Connect button.

 38

7. Enter the WEP Key 1 (which we set on Router) then click on Connect.

Systems after establishing connection:

8. IP Addresses are given to the end-devices automatically once we connect it to the

wireless router.

End Device IP Address Subnet Mask

PC1 192.168.0.101 255.255.255.0
Laptop1 192.168.0.102 255.255.255.0
 39

9. Ping the systems Laptop1 from PC1.

 40

Ques 11
Introduction to Network Address Translation

Ans.
NAT (Network Address Translation) is a mechanism where a device performs modifications
to the TCP/IP address/port number of a packet and maps the IP address from one realm to
another (usually from private IP address to public IP address and vice versa). This works by
the NAT device allocating a temporary port number on the public side of the NAT upon
forwarding outbound packet from the internal host towards the Internet, maintaining this
mapping for some predefined time, and forwarding the inbound packets received from the
Internet on this public port back to the internal host.

NAT devices are installed primarily to alleviate the exhaustion of IPv4 address space by
allowing multiple hosts to share a public/Internet address. Also due to its mapping nature (i.e.
a mapping can only be created by a transmission from an internal host), NAT device is
preferred to be installed even when IPv4 address exhaustion is not a problem (for example
when there is only one host at home), to provide some sort of security/shield for the internal
hosts against threats from the Internet.

Despite the fact that NAT provides some shields for the internal network, NAT solution is
different from firewall solution. NAT is not a firewall solution. A firewall is a security solution
designed to enforce the security policy of an organization, while NAT is a connectivity solution
to allow multiple hosts to use a single public IP address. Understandably both functionalities
are difficult to separate at times, since many (typically consumer) products claims to do both
with the same device and simply label the device a “NAT box”. But we do want to make this
distinction rather clear, as PJNATH are a NAT traversal helper and not a firewall bypass
solution (yet).

Types of NAT:

There are three different types of NATs. People use them for different reasons, but they all
still work as a NAT.

• Static NAT:
When the local address is converted to a public one, this NAT chooses the same one.
This means there will be a consistent public IP address associated with that router or
NAT device.

• Dynamic NAT:
Instead of choosing the same IP address every time, this NAT goes through a pool of
public IP addresses. This results in the router or NAT device getting a different address
each time the router translates the local address to a public address.

• PAT:
PAT stands for port address translation. It’s a type of dynamic NAT, but it bands several
local IP addresses to a singular public one. Organizations that want all their employees’
activity to use a singular IP address use a PAT, often under the supervision of
a network administrator.
 41

The ``natted'' subnet uses the private IP addresses

• Private IP addresses are NOT usable on the Internet… otherwise:
• Networking within the private IP space is exactly like normal host networking.
• Network services and protocols behave the same, etc.

A gateway machine becomes the ``Nat Host''

• Host must be capable of IP Forwarding.
• NAT host has an Exterior interface with a real IP address.
• NAT host has an Interior interface in the private IP space.

Example:

Interior hosts' outgoing traffic is ``translated'' by the NAT Host

• Source IP addresses are changed to the exterior IP address of the NAT Host.
• Source Port numbers are changed to a unique value.
• The translated session must be saved in a State Table.
• Return traffic is matched in the State Table and Destination IP and Port numbers are modified
accordingly.
 42

Ques 12
Overview of different interfaces in router

Ans.
Main Interfaces of Cisco Devices
It is a network infrastructure that allows physical signals to be exchanged by connecting
transmission media to interfaces such as Cisco devices, PCs, and servers to form a link. While
“interface” means “boundary,” a network interface is the boundary between “0” and “1”
digital data and physical signals, such as electrical signals.

Cisco devices can be equipped with many different types of interfaces, the main ones being
the following:
Ethernet Interface:
It is an interface for building an Ethernet LAN. The most common connector for Ethernet
interfaces is the RJ45 connector and the cable is a UTP cable. In addition to LANs, Ethernet is
now widely used as an interface to connect to WAN services as well.
Serial Interface:
This interface is used to connect the router to a leased line or other WAN service. There are
many standards for serial interfaces, each with different connectors and cables. A commonly
used serial interface is a smart serial connector with a smart serial cable connected to a smart
serial connector.
ISDN Interface:
An interface for connecting routers to the ISDN network. New ISDN networks are no longer
used, but some previously operational networks still make use of the ISDN interface.
Console Port/ AUX Port:
These are interfaces used to configure Cisco devices rather than interfaces for connecting to
the network. In terms of notation, we generally use “port” rather than “interface”.
 43

Depending on how many interfaces Cisco devices can be added or changed at a later time,
the following are available:
Fixed devices basically cannot be added or changed at a later time. Modular devices allow
you to add or change the type and number of interfaces by adding or replacing modules at a
later date. Modular devices are larger devices for relatively large-scale applications, also
known as chassis devices.
Interface Name:
Routers and switches come with multiple interfaces of various types. When configuring an
interface or creating a network diagram, you need to be able to identify the interface by its
name rather than a simple number. The format is as follows.

For example, the interface name is determined as “GigabitEthernet0/1”. You can use the
abbreviated form “gi0/1” or “g0/1”.
The following table summarizes the main interface types

Interface <interface-type>
Ethernet Ethernet
FastEthernet FastEthernet
GigabitEthernet GigabitEthernet
10GigabitEthernet TenGigabitEthernet
Serial Serial
ISDN BRI BRI
For fixed devices, <slot> is basically a fixed zero. Some fixed-type devices have a slot for a
network module, and you can specify the slot number for that slot. In the case of a modular
device interface, it specifies the slot number in which the module is inserted. <port> is simply
the port number. Note that router port numbers start at “0”, but Catalyst switches have their
port numbers starting at “1”.
Note that the interface name of the console port is “con 0” and the interface name of the
auxiliary port is “aux 0”. The console port and auxiliary port are not used to send and receive
data. They are used to exchange configuration and confirmation commands and command
execution results. When configuring a console or auxiliary port, enter “line con 0” or “line aux
0” instead of the interface configuration mode to go to line configuration mode and execute
commands.
 44

Ques 13
Implement IP Subnetting in IPV4

Ans.
Steps:
1. Pick three devices and three routers and connect them as shown.

2. Now Assign IP addresses to all. i.e., 3 devices and 3 routers, of different networks. As:-
For PC0 For PC1 For PC2

3. Also assign addresses for serial ports of routers. As Router1 is connected to two other
routers we will have to set two serial ports.
4. Switch On the port status of all the routers.
5. Now for Static Routing set the router to config mode and set no ip route with the
network address of the destination device (for both the destination networks), its
subnet mask and the serial port address of the next hop (i.e., the router). As:-
 45

6. Now ping the systems as:-

 46

Ques 14
Implement IP routing using RIP

Ans.
Steps:
1. Select 3 devices and 3 routers and connect them.

2. Now assign IP Address to all the devices to FastEthernet 0/0 ports.

3. Also assign addresses for serial ports of routers. As router 1 is connected to 2 other
routers we will have to set 2 serial ports.

End-Device IP Address Subnet Mask

PC0 192.168.0.1 255.255.255.0
PC1 192.168.1.1 255.255.255.0
PC2 192.168.3.1 255.255.255.0
Connecting Device Ethernet IP Serial IP
Router0 192.168.0.10 Serial 2/0: 192.168.10.1
Router1 192.168.1.10 Serial 2/0: 192.168.10.2
Serial 3/0: 192.168.20.2
Router2 192.168.3.10 Serial 2/0: 192.168.20.1

4. Switch on the port status for all the routers.

5. Now go to router → Go to config

 47

6. In config click on RIP and add all the IP addresses used as Gateways.
 48

7. Now ping PC0 and PC2.

 49

Ques 15
Implement IP routing using IGRP

Ans.
In a host network, the Interior Gateway Routing Protocol (IGRP) is a proprietary distance
vector routing protocol that is used to exchange routing information. Cisco was the one who
came up with the idea.
The Internet Geolocation Routing Protocol (IGRP) regulates the transfer of routing
information among linked routers in the host network or autonomous system. The
protocol guarantees that every router’s routing table is kept up to date with the most direct
route available. IGRP also helps to minimize routing loops by updating itself in response to
changes that occur on the network and by implementing error management.
The following are the characteristics of the IGRP (Interior Gateway Routing Protocol):
1. The Internet Group Routing Technology (IGRP) is a distance-vector routing protocol
created by Cisco.
2. In addition to bandwidth, delay (by default), reliability, load, and MTU are all
measured in the IGRP protocol.
3. It transmits updates every 90 seconds, with a hold-down time of 280 seconds
between each broadcasting session.
4. When network changes occur, triggered updates are utilized to expedite the
convergence process.
5. The IGRP router command needs the inclusion of an AS number.
6. For routers to communicate routing information, they must be in the same
Associated System Number (AS).
7. The maximum number of hops allowed by IGRP is 255. It has a default value of 100
and is often changed to 50 or less.
8. The IGRP AD value is 100.

The International Geophysical Research Program (IGRP) has two primary objectives:
1. Its primary function is to provide routing information to all linked routers within its
border or inside its autonomous system
2. It will automatically update whenever the network topology changes. Every 90
seconds, it sends out a notice to its neighbors to inform them of any new
modifications.
The IGRP performs a variety of functions:
Interior Gateway Routing Protocol (IGRP) was developed by Cisco in response to the
restrictions of the Routing Information Protocol (RIP), which manages a maximum hop
count of 15 per connection. The Internet Geolocation Routing Protocol (IGRP) allows for
a maximum hop count of 255. The fundamental two objectives of the IGRP are as follows:
1. Route information should be sent between all linked routers inside its border or
autonomous system.
2. Continue to update anytime there is a topological, network, or route change that
takes place.
Every 90 seconds, the IGRP broadcasts to its neighbors a notice of any new modifications
as well as information about its current condition.
 50

IGRP is responsible for maintaining a routing table with the most optimum route to the
corresponding nodes and networks inside the parent network, as determined by the
parent network. Given that it is a distance-vector protocol, the IGRP calculates the metric
for the shortest route to a certain destination based on a number of different criteria.
Advantages:
1. The procedure is simple and uncomplicated.
2. It considers the latency, bandwidth, reliability, and load of a network connection
while calculating the score. Consequently, it is quite accurate when it comes to
selecting the most suited approach.
3. The use of composite metrics.
4. Configuration is straightforward.
5. When compared to RIP, it has more scalability (255 hops, 100 by default).
Disadvantages:
1. The hop count is limited to 15; if a packet has travelled through 15 routers and still
has another router to travel to, it will be discarded.
2. Does not support a variable-length subnet mask (VLSM), which means that it sends
routing updates based only on a fixed-length subnet mask (FLSM) or routes that fall
on classful boundaries. As a result, RIP V1 will not function on a network that has
been subnetted beyond the standard /8, /16, and /24 (255.0.0.0, 255.255.255.0) or
Class A, B, and C network borders (255.0.0.0, 255.255.255.0).
3. Convergence occurs slowly, particularly on large networks.
4. Doesn’t know how much bandwidth is available on a given connection.
5. Doesn’t allow numerous pathways for the same route.
6. Routing updates may use a substantial amount of bandwidth since the whole
routing database is delivered whenever the state of a connection changes. Routers
are prone to routing loops.
Setting configuration in CLI-
51
 52

Connections:

Real Time Simulation:

 53

Ques 16
Managing traffic with Standard IP & Extended IP Access List

Ans.
First step is to configure the CISCO Routers.

Configuration of Router0 using RIP protocol is as follows:

Router>en
Router#config t
Enter configuration commands, one per line. End
with CNTL/Z.
Router(config)#int s2/0
Router(config-if)#ip add 192.168.10.1 255.255.255.0
Router(config-if)#clock rate 64000
Router(config-if)#no shutdown
%LINK-5-CHANGED: Interface Serial2/0, changed
state to down
Router(config-if)#int f0/0
Router(config-if)#ip add 192.168.20.1 255.255.255.0
Router(config-if)#no shutdown
%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface
FastEthernet0/0, changed state to up
Router(config-if)#router rip
Router(config-router)#network 192.168.10.0
Router(config-router)#network 192.168.20.0
ISSN: 2278 – 7798
Router(config-router)#end
Router#
%SYS-5-CONFIG_I: Configured from console by console
Router#write memory
Building configuration...
[OK]

Configuration of Router1 using RIP protocol is as follows:

Router>en
Router#config t
Enter configuration commands, one per line. End
with CNTL/Z.
Router(config)#int s2/0
Router(config-if)#ip add 192.168.10.2 255.255.255.0
Router(config-if)#clock rate 64000
Router(config-if)#no shutdown
%LINK-5-CHANGED: Interface Serial2/0, changed
state to up
Router(config-if)#int f0/0
Router(config-if)#ip add
 54

%LINEPROTO-5-UPDOWN: Line protocol on Interface

Serial2/0, changed state to up
192.168.30.1 255.255.255.0
Router(config-if)#no shutdown
%LINK-5-CHANGED: Interface FastEthernet0/0,
changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface
FastEthernet0/0, changed state to up
Router(config-if)#router rip
Router(config-router)#network 192.168.10.0
Router(config-router)#network 192.168.30.0
Router(config-router)#exit
Router(config)#access-list 10 deny host 192.168.20.2
Router(config)#access-list 10 permit 192.168.20.0 0.0.0.255
Router(config)#interface fast 0/0
Router(config-if)#ip access-group 10 out
Router(config-if)#end
%SYS-5-CONFIG_I: Configured from console by console
Router#write memory
Building configuration...
[OK]
Router#

Configuration of PC:
PC0:

B. Extended ACL:
Similar to the standard ACL firstly routers are configured and then the extended number
ACL is configured. Following Figure shows the network model for extended ACL.
 55

Configuration of Router0 using RIP Protocol is as follows:

Router>en
Router#config t
Enter configuration commands, one per line. End with
CNTL/Z.
Router(config)#int s/20
Router(config-if)#ip add 10.10.10.1 255.0.0.0
Router(config-if)#clockrate 64000
Router(config-if)#no shutdown

%LINK-5-CHANGED:Interface Serial 2/0, changed state to down

Router(config-if)#int f0/0
Router(config-if)#ip add 20.20.20.1 255.0.0.0
Router(config-if)#no shutdown
%LINK-5-CHANGED:Interface FastEthernet2/0, changed state to up
%LINEPROTO-5-UPDOWN:Line protocol on Interface
FastEthernet0/0, changed state to up
Router(config-if)#router rip
Router(config-router)#network 10.0.0.0
Router(config-router)#network 20.0.0.0
Router(config-router)#exit
Router(config)#access-list 101 deny tcp host 20.20.20.2
10.10.10.2 0.255.255.255 eq telnet
Router(config)#access-list 101 permit tcp 20.0.0.0
0.255.255.255 10.10.10.2 0.255.255.255 eq telnet
Router(config)#access-list 101 permit ip any any
Router(config)#int f0/0
Router(config-if)#ip access-group 101 in
Router(config-if)#
%LINK-5-CHANGED: Interface Serial2/0, changed
state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface
Serial2/0, changed state to up
 56

Configuration of Router1 using RIP protocol is as follows:

Router>en
Router#config t
Enter configuration commands, one per line. End
with CNTL/Z.
Router(config)#int s2/0
Router(config-if)#ip add 10.10.10.2 255.0.0.0
Router(config-if)#clock rate 64000
Router(config-if)#no shutdown
%LINK-5-CHANGED: Interface Serial2/0, changed
state to up
Router(config-if)#int f0/0
Router(config-if)#
%LINEPROTO-5-UPDOWN: Line protocol on Interface
Serial2/0,
changed state to
up ip add
30.30.30.1
255.0.0.0
Router(config-
if)#no shutdown
%LINK-5-CHANGED: Interface FastEthernet0/0,
changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface
FastEthernet0/0, changed state to up
Router(config-if)#router rip
Router(config-router)#network 10.0.0.0
Router(config-router)#network 30.0.0.0
Router(config-router)#line vty 0 4
Router(config-line)#password 1234
Router(config-line)#login
Router(config-line)#exit
Router(config)#enable secret qwerty
Router(config)#

Verify the Telnet Access:

Figure shows that when the host i.e. PC1
connected to Router0 tries to telnet serial
port connected to Router1, the access-list
permits the host to route the packets.

Router 0 host can Telnet Router 1

57

Figure shows that when the host

i.e. PC0 connected to Router0
tries to telnet serial port
connected to Router1, the
access-list denies the host to
route the packets

Router 0 host can’t Telnet Router

1